A Novel TRIM9 Protein Promotes NF-κB Activation Through Interacting With LvIMD in Shrimp During WSSV Infection

Mingzhe Sun,Shihao Li,Xuechun Li,Fuhua Li,Songjun Jin,Jianhai Xiang

doi:10.3389/fimmu.2022.819881

Abstract

The TRIpartite Motif (TRIM) proteins play key roles in cell differentiation, apoptosis, development, autophagy, and innate immunity in vertebrates. In the present study, a novel TRIM9 homolog (designated as LvTRIM9-1) specifically expressed in the lymphoid organ of shrimp was identified from the Pacific whiteleg shrimp Litopenaeus vannamei. Its deduced amino acid sequence possesses the typical features of TRIM proteins, including a RING domain, two B-boxes, a coiled-coil domain, a FN3 domain, and a SPRY domain. The transcripts of LvTRIM9-1 were mainly located in the lymphoid tubules of the lymphoid organ. Knockdown of LvTRIM9-1 could apparently inhibit the transcriptions of some genes from white spot syndrome virus (WSSV) and reduce the viral propagation in the lymphoid organ. Overexpression of LvTRIM9-1 in mammalian cells could activate the promoter activity of NF-κB, and an in vivo experiment in shrimp showed that knockdown of LvTRIM9-1 reduced the expression of LvRelish in the lymphoid organ. Yeast two-hybridization and co-immunoprecipitation (Co-IP) assays confirmed that LvTRIM9-1 could directly interact with LvIMD, a key component of the IMD pathway, through its SPRY domain. These data suggest that LvTRIM9-1 could activate the IMD pathway in shrimp via interaction with LvIMD. This is the first evidence to show the regulation of a TRIM9 protein on the IMD pathway through its direct interaction with IMD, which will enrich our knowledge on the role of TRIM proteins in innate immunity of invertebrates.

Highlights

White spot syndrome virus (WSSV), the causative agent of white spot syndrome (WSS), could cause 100% mortality within 7–10 days and lead to serious economic loss in shrimp aquaculture worldwide [1, 2]
The transcript of LvTRIM9-1 obtained from the transcriptome database of L. vannamei was validated by PCR and confirmed by sequencing
LvTRIM9-1 and LvTRIM9 shared the same functional domains (Figure 1B), the similarity between their amino acid sequences was around 41.87%

Summary

Introduction

White spot syndrome virus (WSSV), the causative agent of white spot syndrome (WSS), could cause 100% mortality within 7–10 days and lead to serious economic loss in shrimp aquaculture worldwide [1, 2]. The Toll and IMD pathways, two NF-kB signaling pathways mediated by the transcriptional factor Dorsal and Relish, can regulate the expression of various antimicrobial peptides (AMPs) that directly kill foreign pathogens. These two pathways could be subverted and hijacked by the virus to favor its propagation in shrimp during WSSV infection [1]. Activation of Toll or IMD pathway promotes the expression of several WSSV immediate early genes, like wsv and wsv303 [4, 5] Activation of these two pathways might work as a double-edged sword in shrimp during WSSV infection

Methods

Results

Conclusion